There's been a recent change with the CAME-TV ARGO and MINI 3 Batteries. These stabilizers have now moved to 'Battery Cases' that hold popular and easily available Samsung 18650 Batteries. This is a big bonus for many as you no longer have to purchase a proprietary battery if you want extended run times. Here's a video of what it looks like, and what's included.
The one thing CAME-TV has mentioned is that it's important to remove the 18650 batteries from the battery cases when not in use. Otherwise it's possible the batteries can drop down below a voltage that most chargers see as a possible bad battery. Then you'd end up having to replace the Batteries. This is common for many types of batteries as it could be an indication of a bad cell, or bad battery. If the battery is good, it's more like 'sleep mode' and it's possible to recover a good battery from this if you know how (i'll let you do research on that).
So if you're looking to stock up on extra power, here's an example of these 18650 Batteries that customers seem to have positive reviews with:
Samsung 18650 Rechargeable Batteries
And you can find additional information about the CAME-TV ARGO and MINI3 Gimbals at the CAME-TV website (here).